However, the shares powered back to close up 38p at £11.42 after Mr Finlayson met analysts and appeared to have convinced investors that the company’s longer-term growth prospects remained intact.

The downgraded outlook followed BG’s shock warning on Hallowe’en last year that it expected no increase in oil and gas output in 2013, against expectations of double-digit growth. The news wiped £6bn from the company’s value in one day.

Mr Finlayson, who took over from Sir Frank Chapman on January 1, said: “Right now I understand we need to rebuild trust in our ability to execute.”

BG Group’s downgraded production outlook came as it reported a 12pc fall in pre-tax profits for 2012, to $6.4bn (£4.1bn), in large part because of previously announced write-downs on the value of US shale gas assets.

Fourth-quarter pre-tax profits fell 11pc, to $1.6bn, on revenues that were 5pc lower because of fewer deliveries of liquefied natural gas (LNG) cargoes and a 2pc fall in oil and gas output.

Overall in 2012, average daily oil and gas production rose 2.5pc to 657,000 barrels of oil equivalent per day (boepd), in line with revised expectations following the Hallowe’en warning.

However, Mr Finlayson said that production in 2013 may slip lower, giving a range of between 630,000 and 660,000 boepd. Given that start point and the impact of a deal to sell a stake in its Queensland Curtis LNG project in Australia to China’s CNOOC, it was clear that the 2015 target of 1m boepd would not be reached, Mr Finlayson said.

He insisted he did not see any “systemic” problems behind BG Group’s production warnings, adding issues had been focused around specific problems in Egypt and in the UK. Production in the UK in 2012 was hit by shutdowns at North Sea fields that BG Group does not operate but in which it has a stake, including Elgin-Franklin, which was closed after a gas leak last year.

UK North Sea fields that BG Group did operate also ran into problems, including a shortage of floating accommodation that prevented improvement work being carried out.

Mr Finlayson is due to give a strategy update in May but said BG Group would build on its “distinctive strengths” of “world-class exploration, a unique LNG model and commercial agility”.

He also played down recent takeover speculation. “BG has been a perennial takeover target ... so staff worry less about it than at some companies,” he said.

“For me, it’s very simple: I’m here to do the best possible job to get the best possible value for shareholders. That comes from getting our short-term production right and developing our long-term projects. We will see what happens.”

BG Group raised its fourth quarter dividend by 10pc, to 14.26 cents per share, payable on April 17.